Any exchange 2010 schema related task need to be done before or after Domain controller upgrade to 2012 R2?

At our company, we plan on migrating domain controllers from 2008 R2 to 2012 R2. We currently are running exchange 2010 (eventually moving to 2013 sometime next year). Do we have to run any exchange related "schema" items before or after we run domain and forest prep on the 2012 DC servers? I just dont want exchange to break when this happens.

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